| 摘要 |
PRODUCTION OF HIGH STRENGTH SEAMLESS STEEL PIPE WITH SUPERIOR RESISTANCE AGAINST SULFIDE STRESS CORROSION CRACKING This invention is to obtain both properties of high strength and sulfide stress corrosion crackingresistance, which have been difficult to be simultaneously attained, under an inexpensive ingredient system in seamless steel pipes for use in oil well pipes, line pipes, pipe lines for chemical plants, etc. The seamless steel pipe possessing a yield strength of not less than 75 kgf/mm2 and excellent sulfide stress corrosion cracking-resistance in combination can be obtained without producing quenching cracks by increasing particularly the content of C and ultimately decreasing impurities such as P and S in a Cr-Mo steel as a raw material, performing quenching at a relatively low cooling rate of from 1 to 50.degree.C/s after the heating, and performing annealing in a relatively high temperature range from 680.degree.C to Ac1 transformation point. |
